Outer Web Research Articles

Detecting and representing relevant web deltas in WHOWEDA

In this paper, we present a mechanism for detecting and representing changes, given the old and new versions of a set of interlinked Web documents, retrieved in response to a user's query. In particular, we show how to detect and represent Web deltas, i.e., changes in the Web documents that are relevant to a user's query in the context of our Web warehousing system called WHOWEDA (Warehouse of Web Data). In WHOWEDA, Web information is materialized views stored in Web tables in the form of Web tuples. These Web tuples, represented as directed graphs, can be manipulated using a set of Web algebraic operators. In this paper, we present a mechanism to detect relevant Web deltas using Web algebraic operators such as the Web join and the outer Web join. Web join is used to detect identical documents residing in two Web tables, whereas, outer Web join, a derivative of Web join, is used to identify dangling Web tuples. We show how to represent these changes using delta Web tables. We develop formal algorithms for the generation of delta Web tables identifying Web documents which have been added, deleted, or modified since the last query.

Effect of Posttensioning on Rotational Stiffness of Wood Joints

The moment-rotation behavior of full-size Warren truss timber connections, using posttensioning as a possible reinforcement scheme, was investigated and compared with the current method of using gusset plates. Four joint configurations were tested using three posttensioning levels. The stiffness of the joints was calculated and is presented in this technical note. Based on the results of posttensioned joints and earlier experimental investigations, it was found that the increase in joint rotational stiffness, due to transverse posttensioning is a function of the number of connector rods in the joint zone for both inner (compression) and outer (tension) web members, and the increase in joint rotational stiffness due to transverse posttensioning is a function of the posttension level for outer (tension) web members.

Criteria for the age determination of the HawfinchCoccothraustes coccothraustes

Criteria for ageing Hawfinches on a semi‐quantitative basis are analyzed. Age/sex classes can be recognized by scoring rectrix abrasion, width of the outer web of the sixth primary and sharpness of the greater alula feather. Based on these three criteria, age determination appears always possible.

Cercomacra manu, a New Species of Antbird from Southwestern Amazonia

Cercomacra manu, a New Species of Antbird from Southwestern Amazonia

Finite Element Model for RHS Double Chord K‐Joints

A finite element elastic‐plastic model for separated double chord gap K‐joints of steel rectangular hollow sections (RHS), is presented. The model treats a single chord member as composed of a plate representing the inner web and a channel depicting the top and bottom flanges and the outer web, respectively. Triangular and rectangular flat shell elements are used to discretize the inner web plate, whereas plane stress elements are employed for the branch members. The channel consists of a grillage of beam elements. The analysis extends beyond the elastic limit and accounts for strain hardening and material nonlinearity. A comparison of theoretical predictions with the experimental results of 12 K‐joint specimens of a previous study shows fair agreement.

A twin shear beam model for double chord RHS joints

A finite element elasto-plastic analysis of a twin shear beam model, developed to shed light on the behavior of separated double chord gap joints of rectangular hollow sections (RHS), is presented. The model treats a single beam member as composed of a plate simulating its inner web and a channel representing top and bottom flanges and the outer web. The twelve degrees of freedom (DOF) nonconforming plate bending element and the eight DOF plane stress elements are used to form a plate element for the inner web, while the channel consists of a grillage of beam elements. The analysis, extended beyond the elastic limit, accounts for strain hardening and material nonlinearity. A comparison of theoretical predictions with the experimental results of 24 specimens shows generally good agreement. The mean ratios of theoretical to experimental values are 0.97 and 0.87 for elastic stiffness and carrying capacity measured at a post elastic deformation limit.

The strength of beam-to-staggered column connections of rectangular hollow sections

Not infrequently, a column segment within the a storey of a structural frame must be laterally displaced to accommodate the requirements of the users of a building. The ensuing beam-to-staggered column connection is the subject of this paper. Results are reported of an experimental programme of such connections consisting of square hollow section columns sandwiched between rectangular hollow section (RHS) beams. Specimens tested had beam depth-to-width ratios varying from 0.40 to 2.50. The clear stagger distance-to-beam depth ratio was either 0.5 or 1.0. Two theoretical strength limits are developed employing a modified yield line method that incorporates both yield and ultimate stress values. It is found that the observed failure load lies generally in the range between the two strength limits predicted by theory. The variation of the beam outer web efficiency with beam aspect ratio and gap-to-depth ratio is also discussed.

A dual web potato harvester

Using information gathered from trials with a dual web potato digger, a single-row, power take-off driven harvester was manufactured. The machine has dual rod-link webs running one within the other. The outer web rods are spaced 51 mm apart and the inner web rods 32 mm apart.

Quantitative and Qualitative Age and Sex Criteria of the Starling, Sturnus Vulgaris, in March

Age and sex criteria are studied of 74 Starlings, 39 ♂ ♂ (14 first-year) and 35 ♀ ♀ (27 first-year), in March. Weight, bill length, wing length, lengths of the iridescent parts of the throat and breast feathers, lengths of the white tips on the breast and abdomen and the amount of black colour on the bill are treated quantitatively. Qualitatively treated are: gloss of the plumage, gloss on the lesser secondary coverts, gloss on the breast, pointedness of breast and abdominal feathers, length of the throat feathers, gloss on the end of the outer web of the secondaries, colour of the under wing coverts and form of the upper tail coverts. Skull ossification was expected to be completed in March, but finding 7 birds with an incompletely ossified skull, this character has been included in our study.

AN ADAPTATION TO PRODUCE LARGE LIFT FORCES IN SMALL SHORT-WINGED BIRDS

In some passerine birds which have short wings with rounded tips the outer web of the primaries is emarginated towards the tip. This enables these birds to produce a series of slots between these feathers. The multislotted wing tip so formed helps these birds to lift large wing loads per gram of pectoralis major muscle at takeoff.

The Wartime Repair of Bristol Aeroplanes

TWO items which frequently appeared on the repair lists for the Beaufort and Beaufighter, were (i) the main inter‐spar ribs to which the fuselage is attached, and (ii) the ribs carrying the nacelle structure (FIG. 26). The attachment ribs for the fuselage were usually known as the box ribs, a term derived from their form of construction which consisted of inner and outer alclad webs with top booms of extruded angfe section and built‐up bottom booms of box section forming the link between the longerons of the front and rear fuselages. On the Beaufighter the ribs were attached to the spars by means of extruded angles, extruded channels being employed on the Beaufort (FIG. 27). The ribs were further stiffened by inter‐web members of channel section. Each attachment rib for the nacelle structure consisted of an alclad web with a top and bottom boom of extruded angle section and secured to a bracing of square section steel tubes.

An Outbreak of Pox in Turkeys with Notes on Diagnosis and Immunization

ON JUNE 3, 1937, two Bronze turkey poults (Fig. 1) were presented at the Laboratory of Animal Pathology and Hygiene, University of Illinois, for diagnosis. The general condition appeared good and both poults manifested normal vigor, alertness, and appetite. Locomotion was somewhat impaired mechanically by a large exuberant swelling on the right foot of each specimen. This lesion, apparently originating within the outer web and mushrooming over the toes, was moderately firm and of uniform texture throughout, yet quite pliable to manipulation. The surface integument presented an irregular papillomatous appearance without evidence of an active inflamatory involvement.Except for the lesion at the right commissure of the mouth of the individual to the right in Figure 1, no abnormality was observed on clinical or necropsy examination of either bird. This lesion, unlike those of the feet, was suggestive of the early post-vesicle stage of fowl-pox infection. It was learned that .

The California Sage Sparrow

SUBSPECIFIC CHARACTERS-Resembles Amp?zispiza belli belli, but Size somewhat greater, and coloration throughout very much paler; resembles Amphispzza belli nevadensis, but size very much less, and coloration slightly darker. TYPE-~ adult; No. 5789, Coll. J. G.; Seymour Creek Meadow, 5500 feet elevation, Mount Pinos, Ventura County, California; June 27, 1904; collected by J. Grinnell. DEscRIp’ rIoN-Lower surface white; sides, flanks and crissum faintly tinged with ochraceous buff, the former with narrow inconspicuous dusky shaft-streaks; sides of chest more distinctly streaked with slate; spot in middle of breast, submaxillary stripe, lores, region immediately beneath eyes, and extreme forehead, slate; spots above lores, one on forehead just back of culmen, eyelids, maxillary region and throat, pure white; rest of head, including auricular region, sides of neck and nape, clear gray; back and rump drab gray; middle of back with narrow dusky shaft-streaks; wings and tail blackish, strongly edge! with pale clay color; outer web of outer tail-feather, and inner web of same for about 2 millimeters at tip, abruptly white. MEASUREMENTSA. 6. nevademis Fazg 66 ?i i Av. 80.2 Max. 82.5 Min. 7% Av. 81.2 Max. 85.5 Min. 79. A. 6. nevau’ eensis { ;yi;g Av. 74.1 Max. 75 Min. 73.5 49 0 Av. 76 Max. 76.5 Min, 75. A. 6. canescem j Wing Av. 71 Max. 73 Min. 69.

The Drumming of the Snipe

IT is disputed whether the snipe's drumming—a curious noise, suggestive of a miniature threshing machine—is made by the bird with its wings or by its tail, or by both wings and tail. Some recent observations incline me strongly to believe that the tail plays at any rate the more important part. During the performance the bird flies at a great height round and round in a wide sweeping circle. At intervals he makes a sudden and rapid descent, holding his wings partly flexed and his tail spread to its full extent. The outermost tail feather on either side points outward at a greater angle than those adjoining it, so that when the bird is watched through a good field glass daylight shows between it and the next; and, if I am right in my view, the drumming sound is due to the rush of air against this isolated feather. The snipe's tail feathers seem so puny that it is at first difficult to believe that they can produce so great a result. But if an outer one be taken—it is slightly scimitar-shaped with the outer web much reduced—and swung rapidly through the air, the drumming noise may be distinctly heard, though it seems but a very faint echo of the loud throbbing hum that startles one when it suddenly descends from an ethereal height, and the small bird is descried, hardly more than a speck to the naked eye, circling round in wild career, and now and then swooping headlong downwards and thrilling the air with his weird music.

Progressive Variation in the Malayan Peacock-Pheasant

IN looking over the specimens of this species (Polyplectrum bicalcaratum) in the Indian Museum, I have come across a most interesting skin of an adult male, showing variation in the direction of greater ornamentation. Normally, this peacock-pheasant has ocelli only on the wings and tail and the upper part of the back; but in the present specimen several of the black-speckled buff feathers of the back, immediately below the ocellated region, have clusters of the small spots richly glossed with green like the ocelli, the rest of the black speckling of the feather remaining normal. The green specks are always near the end of the feather, in the position occupied by the ocelli. Furthermore, this bird has the long under-tail-coverts decorated near the tip of the outer webs with a not very bright green-glossed ocellus, the inner webs merely showing black patches, such as are normal on both webs of these feathers in other specimens. Thus this individual presents on the upper surface a variation which might be advantageous in sexual selection, and beneath a similar enhancement of beauty which could hardly be of any use, since the Polyplectrons show off in an attitude which prevents any display of the under-tail-coverts. It is therefore interesting as showing how the beauty of a species might be enhanced both with and without the assistance of preferential mating on the part of the females.

Racket Feathers

YOUR able reviewer of Meyer and Wiglesworth's “Birds of Celebes” (NATURE, April 26), criticising the arguments used to account for the formation of the racket tail feathers of the parrot, Prioniturus (as an inherited effect of mechanical attrition on objects against which the tail is liable to be brushed—boughs, walls of nesting-hole, &c.), asks the pertinent question, why so few exposed feathers, such “as the external rectrices and remiges of all birds, and specially the lengthened feathers of wedge-shaped tails (Dicrurus) are neither bare nor racket-shaped nor incipiently so.” The insignificant length of the outer rectrices of Dicrurus perhaps safeguards them; when these feathers are longer, as in the closely-allied Bhringa and Dissemurus, they are racket-shaped. As to the remiges and rectrices of birds generally, one feather overlies and to a great extent protects the next; but still, the outer webs are always very much narrowed in the outermost and most exposed feathers, less narrowed in the next, and so on till in the middle of the wing and tail (where they are well protected on both sides) they are not narrowed at all. But, while normal wing and tail feathers are exposed to attrition on one web only, long feathers standing well out from the rest are liable to have the web frayed on both sides of the shaft as far as they project beyond the other feathers, and to some extent where they rest upon the other feathers through friction against the latter. It is assumed that at some period earlier in the history of the race these elongated feathers were of the usual simple shape, but they are now known to issue from the follicles displaying peculiarities which are often much the same as those obtained by scraping an ordinary feather with a knife—namely, if the shaft is stiff and not very long, a small terminal spatule is formed (as in Prioniturus, Parotia); if the shaft is long and weak, a large spatule (as in Tanysiptera, Loddigesia). A difficulty, perhaps, to the acceptance of the theory is its apparent consequence—that epidermal (in a sense, dead) structures, like feathers, possess the power of transmitting: mutilations to posterity. For my own part, I think that the modification of shape of the feathers is communicated to the sensitive tissues (much in the same way as the shape of a stick placed in the hand of a blind man is comprehended by him after touching other things with it), and that a corresponding physiological adjustment is made and gradually inherited. The result is probably not an exact recapitulation of the mutilation, but it sometimes appears to be very nearly so.

An Apparently New Elainea from Barbadoes, West Indies

SP. CHAR. (d3 ad. Type, No. I2,018, CoIl. C. B. Cory.) Upper parts dark olive, with basal portion of the feathers on the crown white; outer webs of quills edged with dull brownish white; tail-feathers olive brown, edged with olive green on the outer webs; sides of the head and cheeks dark olive; throat gray; breast and underparts olive gray, faintly tinged with yellow. Length, 6.65; wing, 3.55; tail, 3.30; tarsus, .95; bill, .45. Habitat. Barbadoes, West Indies.